Combining snmp sensors

I have 2 snmp sensors set up to read out the modem state of my LTE router (easy 1 or 0) and to read out the cell technology (2g, 3g, LTE).
I already have a template set up (no earthly idea how I figured it out though, I am still working on it) to translate the cell tech numbers to readable format as so:

        friendly_name: "Cell Technology"
        value_template: >-
          {% set mapper =  {
              '0' : 'Disconnected',
              '1' : 'Disconnected',
              '2' : '2 GPRS',
              '3' : '3 Edge',
              '4' : '4 UMTS',
              '5' : 'HSDPA+',
              '6' : '6 3G HSDPA',
              '7' : '7 3G HSUPA',
              '8' : 'LTE' } %}
          {% set state =  states.sensor.wr11_wan_tech.state %}
          {{ mapper[state] if state in mapper else 'Disconnected' }}
        icon_template: >-
          {% set mapper =  {
              '0' : 'mdi:signal-off',
              '1' : 'mdi:signal-off',
              '2' : '2 GPRS',
              '3' : '3 Edge',
              '4' : '4 UMTS',
              '5' : 'HSDPA+',
              '6' : '6 3G HSDPA',
              '7' : '7 3G HSUPA',
              '8' : 'mdi:signal-cellular-3' } %}
          {% set state =  states.sensor.wr11_wan_tech.state %}
          {{ mapper[state] if state in mapper else 'mdi:signal-off' }}

But whenever the modem disconnects, the last cell tech persists so I’d love to find out how to set up a template that shows the cell tech text if the modem is connected and displays “Disconnected” when the modem is disconnected.
As a bonus I’d love it if the icons could be yellow when connected and grey when the modem is disconnected.
Many thanks for the help!

You could use an availability trigger. While that will report “unavailable” rather than “disconnected”, it’s a more typical approach.

With “modem disconnects” I am pointing to the internal modem of the device. The device itself stays on at all times. It is an snmp value returning 0 or 1 accordingly.

I am living with older co-inhabitants and they get confused when things are named improperly so I need to name things properly if I want them to use this at all.